Bizarre 1903 Underground Banquet Dinner Of The Elites Secret Tunnel Meetings

In 1903, a strange event occurred in a large underground tunnel in Waterloo, lowa. A bunch of elites were celebrating the construction of a "new" sewer system meant to solve the city's flooding problems. Around 450 guests enjoyed a fine dinner at this unusual banquet. But is there more to this story?
Why would anyone host a massive banquet in a sewer?
[Mind Unveiled]